I have an outdoor park with XV2-2t0’s installed throughout. I have received several reports that mobile devices are disconnecting and reconnecting repeatedly and without reason as their signal strengths are full. I can look at the devices in cnmeastro and see that the roaming history shows the devices are roaming to the same AP every minute or two ( ie. <1m ). their internet access works fine when they are connected but then the device just disconnects and reconnects over and over. This is with android and apple. Currently running 6.6.0.2-r5 on all AP’s with fast roaming enabled and 802.11v. It seems as tho stationary devices like TV’s and such are not having this issue. This is a transparent setup where DHCP is handled separately.
Thomas,
I hesitate to jump in here, as there is not quite enough information to know what is really going on. My guess is that devices outdoors ‘see’ huge overlap in coverage, but devices within campers or vehicles have enough penetration attenuation that they do not see AP’s farther away as equals, and so stay stable. If the phones outdoors want to migrate to a single AP, my guess is that the signal quality of that AP is better than any others. Wifi clients generally move on to look for a new AP when they lose synchronization with the current AP - something forces them to scan for a new AP. In a network with huge coverage overlap between AP’s, sync loss is normally from the signal level too high momentarily - the client receiver is overloaded and the packet error rate spikes, even though the RSSI is appear good. SNR might be reported good in cnMaestro, the measurement is only a snapshot, not continuous.
If your outdoor wifi client’s RSSI is in the -50’s or high -60’s, For a OFDM, QAM based receiver, overload usually occurs at about -40 dBm, but the spike in RSSI may be too fast for any device to report it.
I’d try reducing the TX power in the AP’s in 3 dB increments and measure the performance and roaming. Some AP’s will have more coverage than others, so you may not end up with all AP’s at the same power level. I’d try reducing the power on the AP they migrate to first. You may have to go slower with this process that you want. I’m not sure if you’re using AP Groups, Auto RF, or cnMaestro enhanced roaming, and if so, what the roaming threshold is set to. I’ve seen in school situations the same behavior - an AP mounted in a prime location becomes the master AP over some of the AP’s installed around it, and tends to ‘gather up’ and hold onto clients that are walking by, but laptops that are fixed in location work fine.
Hope my 2 cents helps,
2 Likes
Have you tried it without fast roaming?
Thank you for your2 cents. It was very informative and I may take your advice on lower a few AP’s Power levels to see if that may help. Just to clarify, the Mobile devices are having this issue even when indoors and stationary. I am going to setup some APs in Lab and try to replicate this issue if I can.
I have not. I hope it is not caused by Fast roaming as this location as next to 0 cell service and the guest rely on WiFi to take and make calls.
I have a site where I tried “enhanced roaming”. No complaints since deployment a few months ago.
And the main thing people are using there is wifi calling.
I do use Enhance roaming. I have Cambium deployed at several parks across PA and in Texas and so far it is only one Park that is having this issue. Im trying to figure out if it is a setting issue or a Firmware problem
Clients disconnect within 1 min probabilities are as follows:
- Please check if clients are able to succeed DHCP transactions after successful wireless connection.
- Please check overlap of signals, channels if multiple APs are deployed.
- Please check if VLAN assignment is as expected on WLAN/RADIUS
Please share tech-support for further investigation and analysis.
Thank you.